BAP1 safeguards double-strand DNA break repair by limiting DNA end resection [ChIP-Seq]

ABSTRACT: The tumor suppressor BAP1 is frequently mutated in uveal melanoma and has been linked to homologous recombination (HR), yet how it influences DNA double-strand break (DSB) repair pathway choice remains unclear. Here, we identify BAP1 as a critical regulator that restricts DNA end resection to preserve non-homologous end-joining (NHEJ) capacity. Loss of BAP1 leads to aberrant accumulation of H2AK119 ubiquitination at DSBs, driving unscheduled resection in G1-phase cells and impairing recruitment of the anti-resection factor 53BP1. Co-depletion of the resection initiator CtIP restores NHEJ efficiency in BAP1-depleted cells, and pharmacological suppression of H2AK119 ubiquitination reverses these defects, placing unscheduled resection causally upstream of the end-joining failure. RNA sequencing and genome-wide H2AK119ub profiling show that neither the expression of NHEJ and HR genes nor the H2AK119ub landscape at their promoters is appreciably altered by BAP1 loss, supporting a role of altered H2AK119ub at the DSBs. These findings indicate that BAP1 safeguards DSB repair fidelity by preventing hyper-resection, thereby maintaining NHEJ competence. Consistent with this role, BAP1-depleted cells accumulate micronuclei, and BAP1 loss is associated with genomic instability in human uveal melanoma. Together, our results uncover a mechanism by which chromatin regulation constrains resection to coordinate repair pathway utilization.

ORGANISM(S): Homo sapiens

PROVIDER: GSE352106 | GEO | 2026/10/29

REPOSITORIES: GEO